The human spine includes individual vertebras that are connected to each other. Under normal circumstances the structures that make up the spine function are configured to protect the neural structures, allow us to stand erect, bear axial loads, and are flexible for bending and rotation. Disorders of the spine occur when one or more of these spine structures are abnormal. In these pathologic circumstances, surgery may be tried to restore the spine to the normal state and to relieve the patient of pain. Spine surgery for a multitude of spinal disorders is often used for filling voids within a pathologic vertebral body (exemplified by kyphoplasty or vertebroplasty procedures), replacement of a degenerated intervertebral disc with an intervertebral implant device that preserves mobility (disc replacement) or for fusing adjacent vertebral segments (interbody and posterolateral fusions). Fusion works well because it stops pain due to movement at the joints, holds the spine in place after correcting a deformity, and prevents instability and or deformity of the spine after spine procedures such as laminectomies or verterbrectomies.
One area where fusion is applicable is for sacroiliac joint fusion (SIJF). The sacroiliac joint (SIJ) is a firm, small joint that lies at the junction of the sacrum and the pelvis. While most of the vertebras of the spine are mobile, the sacrum is made up of five vertebras that are fused together and do not move. The iliac bones are the two large bones that make up the pelvis. The sacroiliac joints connect the spine to the pelvis. The sacrum and the iliac bones are held together by a collection of strong ligaments. These joints are important in transferring the load of the upper body to the lower body, supporting the entire weight of the upper body when we are erect, which in turn results in stress to this weight-bearing area of the pelvis and spine. Pathologies of the SIJ include degenerative sacroiliitis (arthritis), sacroiliac disruption, tumors and other type of injuries. Sacroiliac joint fusion is used for treating degenerative sacroiliitis, sacroiliac disruption, and for stabilizing the SI joint after sacrectomy or after injury.
There is increasing concensus among surgeons that there is a need to develop devices, instruments, and methods to limit the size of the incision, extensive muscle stripping, prolonged retraction of muscles for visualization, avoidance of neural tissue retraction and injury, and denervation and devascularization that are known to contribute to poorer patient outcome after traditional open surgeries to treat pathologies deep within the body. In many cases these complications lead to permanent scarring and pain that can be more severe than the pain from the initial ailment. Limiting these complications in addition to the operative, general anesthesia, and recovery times are among the goals of this invention and that of percutaneous or minimally invasive surgeries.
This invention addresses the need for bone fusing implants that are used for sacroiliac joint fusion and for implant insertion tools that adhere to the principals of the less exposure surgery (LES) of outpatient surgery, which include minimizing the size of the incision, minimizing extensive muscle stripping, minimizing prolonged retraction of muscles for visualization, and preventing neural tissue refraction and injury.